In general, when surgery is performed, various medical instruments such as a forceps and an endoscope are inserted into a body cavity of a patient, and the medical instrument is manipulated from the outside of the body cavity by a surgeon. Technology in which a contact state of a distal end of the medical instrument with body tissues of the patient is detected and fed back to the surgeon in order to increase operability for the surgeon has been developed. For example, Patent Literatures 1 and 2 disclose technologies in which a sensor (a tactile sensor or a force sensor) configured to detect a contact state of the medical instrument with body tissues of the patient is provided at a distal end of the medical instrument inserted into the body cavity of the patient, and the contact state detected by the sensor is transmitted to the surgeon who manipulates the medical instrument as vibration.